Thiol and sulfur-containing O-(meth)acrylate counpounds and use thereof

ABSTRACT

A sulfur-containing O-(meth)acrylate compound of the following formula (1) is useful as a starting material for a resin composition used in optical applications such as a lens;  
                 
 
     wherein R represents hydrogen atom or methyl group; l represents an integer from 1 to 3; B is  
                 
 
     when B is  
                 
 
     n is 2; m is 1 or 2; A is selected from the following groups:  
                 
 
     wherein m represents 1 or 2; each ring may be substituted by one or more alkyl, alkylthio or alkoxy groups having 1 or 2 carbon atoms; p and q are 0 or 1, while m is 1 when p is 1;  
     when B is  
                 
 
     n is 1; m is 2 or 3; A is selected from the following groups:  
     —(CH 2 ) r —S—(CH 2 ) r —, —(CH 2 ) r —S—S—(CH 2 ) r —, —(CH 2 ) r —S—(CH 2 ) s —S—(CH 2 ) r — and  
                 
 
     wherein r and s are an integer from 1 to 3;  
     when B is  
                 
 
     n is 1; m is 2; A is selected from the following groups:  
     —(CH 2 ) r —S—(CH 2 ) r —, —(CH 2 ) r —S—S—(CH 2 ) r — and —(CH 2 ) r —S—(CH 2 ) s —S—(CH 2 ) r — 
     wherein r and s are an integer from 1 to 3.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to a novel sulfur-containingO-(meth)acrylate compound; a process for preparation of thesulfur-containing O-(meth)acrylate compound, comprisingdithioacetalization, thio-esterification or thiourethanization of anovel thiol compound followed by dehydrohalogenation; an optical resincomposition comprising the sulfur-containing O-(meth)acrylate compound;and an optical resin prepared by polymerization of the composition.

[0003] 2. Description of the Related Arts

[0004] A plastic lens is lighter and less brittle than an inorganiclens, and dyeable, which has been therefore rapidly prevailing in theareas of optical devices such as lenses for eyeglasses and cameras.Currently, the resins which may be widely used for these applications,include those prepared by radical polymerization of diethylene glycolbis (allylcarbonate) (referred to as ‘D.A.C.’). These resins havevarious features such as excellent impact resistance, lightness,excellent tintability, and good processability including machinabilityand abradability. These resins, however, have a low refractive index(n_(d)) of about 1.50 so that it is necessary to increase the centerthickness and the edge thickness, and when such requirements are met,the lens is unavoidably thickened on the whole. Therefore, a lens havinga higher refractive index has been desired.

[0005] Resins with a higher refractive index than D.A.C. resin areknown; for example, polythiourethane resins (e.g., JP-A 63-46213);sulfur-containing O-(meth)acrylate resins (e.g., JP-A 1-128966, 3-217412and 4-161410); and thio(meth)acrylate resins (e.g., JP-A 63-188660 andJP-B 3-59060), in which sulfur atoms are introduced. A polythiourethaneresin is well-balanced in its properties, that is, has a high refractiveindex and good impact resistance and the like. When rapidly polymerizingit, the resin, however, tends to be inhomogeneously polymerized, andthus the polymerization inevitably takes longer time to obtain anoptically homogeneous lens. Furthermore, during processing it by cuttingand abrasion, sulfur odor may generate.

[0006] A sulfur-containing O-(meth)acrylate resin or athio(meth)acrylate resin can be prepared by rapid polymerization bymeans of UV rays or the like. In general, a resin produced may, however,have inadequate strength or impact resistance, that is, it may bebrittle and breakable. Recently, a resin for a lens has been required tohave processing strength suitable for a two-point processing widely usedin the area of a lens for eyeglasses, and a center of a lens foreyeglasses has been being thinner. Thus, there has been a demand for aresin having higher strength and impact resistance. Furthermore, since athio(meth)acrylate compound is less stable, it may gelate or tend to beuncontrollably rapidly polymerized and require complex operations.Therefore, there has been a need for further improvement to solve theseproblems.

SUMMARY OF THE INVENTION

[0007] An objective of this invention is to provide an optical resincomposition which has a good handling properties and can be rapidlypolymerized, and which gives an optical resin having excellent opticalproperties, particularly a high refractive index and excellent impactresistance, as well as generating less unpleasant odor duringprocessing.

[0008] We have intensively attempted to achieve the above object andhave found that some kind of sulfur-containing O-(meth)acrylatecompounds are effective, and have completed this invention. That is tosay, this invention relates to a sulfur-containing O-(meth)acrylatecompound of the following formula (1):

[0009] wherein R represents a hydrogen atom or methyl group; lrepresents an integer from 1 to 3; B is

[0010] when B is

[0011] then n is 2; m is 1 or 2; A is selected from the followinggroups:

[0012] wherein m represents 1 or 2; each ring may be substituted by oneor more alkyl, alkylthio or alkoxy groups having 1 or 2 carbon atoms; pand q are 0 or 1, while m is 1 when p is 1;

[0013] when B is

[0014] then n is 1; m is 2 or 3; A is selected from the followinggroups:

[0015] —(CH₂)_(r)—S—(CH₂)_(r)—, —(CH₂)_(r)—S—S—(CH₂)_(r)—,—(CH₂)_(r)—S—(CH₂)_(s)—S—(CH₂)_(r)— and

[0016] wherein r and s are an integer from 1 to 3;

[0017] when B is

[0018] n is 1; m is 2; A is selected from the following groups;

[0019] —(CH₂)_(r)—S—(CH₂)_(r)—, —(CH₂)_(r)—S—S—(CH₂)_(r)— and—(CH₂)_(r)—S—(CH₂)_(s)—S—(CH₂)_(r)—

[0020] wherein r and s are an integer from 1 to 3.

[0021] This invention also relates to a process for preparation of thesulfur-containing O-(meth)acrylate compound of the above formula (1),comprising dithioacetalizing a thiol compound represented by thefollowing formula (2):

[0022] wherein X represents Cl or Br; R represents hydrogen atom ormethyl group; and l represents an integer from 1 to 3, with a compoundhaving at least one aldehyde group in its molecule; thioesterificatingthe thiol compound with a compound having at least two carboxyl groupsin its molecule or thiourethanizing the thiol compound with a compoundhaving at least two isocyanate groups in its molecule; and thendehydrohalogenating the product.

[0023] The compound of the above formula (2) is also novel, which, as anintermediate of the sulfur-containing O-(meth)acrylate of the aboveformula (1), is covered by this invention.

[0024] Further, this invention also relates to an optical resincomposition comprising the sulfur-containing O-(meth)acrylate compoundof the above formula (1), and a sulfur-containing resin and lens formedby polymerizing the composition.

[0025] The sulfur-containing O-(meth)acrylate compound of this inventionis novel, has improved stability as a monomer and has excellentworkability. The optical resin composition of this invention can berapidly polymerized, giving an optical resin which has excellent opticalproperties, in particular a high refractive index and excellent impactresistance, as well as generates less unpleasant odor during processing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIGS. 1 to 10 are ¹H-NMR charts for the respective compoundsobtained in Examples 1 to 10.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] This invention will be detailed below.

[0028] The sulfur-containing O-(meth)acrylate compound of this inventionrepresented by formula (1) can be prepared from the thiol compoundrepresented by formula(2). Specifically, the compound of formula (1) canbe prepared by ditihoacetalization, thioesterification orthiourethanization of the thiol compound with a compound having afunctional group capable of reacting with the mercapto group of thethiol compound, such as aldehydes, carboxylic acids and isocyanates, andthen dehydrohalogenation of the product.

[0029] The thiol compound of this invention represented by formula (2)can be prepared as follows. 2-Mercaptoethanol, 3-mercaptopropanol or thelike is heated at 10 to 200° C. with a compound such as3-chloropropionic acid, 3-bromopropionic acid,3-chloro-2-methylpropionic acid and 3-bromo-2-methylpropionic acid, inthe presence of a catalyst such as p-toluenesulfonic acid, sulfuric acidand hydrochloric acid, in a solvent, while removing water generated,that is, via a dehydro-esterification. Alternatively, in the light ofstability of the starting material such as 2-mercaptoethanol or3-mercaptopropanol, the dehydro-esterification may be conducted withmild heating of the reaction system under a reduced pressure of 20 to400 mmHg to give the thiol.

[0030] Using the thiol compound of this invention, it is possible tointroduce a sulfur atom into a product molecule to further improve itsrefractive index. Furthermore, the thiol compound of this invention canbe derived to an O-(meth)acrylate compound after reaction in itsmercapto group and then dehydrohalogenation, that is, it can easilyreact with a compound having a functional group capable of reacting witha mercapto group such as aldehydes, carboxylic acids and isocyanates togive a desired sulfur-containing O-(meth)acrylate compound with a highpurity.

[0031] When definition B is

[0032] the sulfur-containing O-(meth)acrylate compound of this inventionrepresented by formula (1) can be prepared with a compound having atleast one aldehyde group and the thiol compound of formula (2) by aprocess comprising the following two steps.

[0033] First, the compound having at least one aldehyde group is heatedwith the above thiol compound at 10 to 200° C. in a solvent, in thepresence of a catalyst such as p-toluenesulfonic acid, sulfuric acid andhydrochloric acid, while removing water generated, that is, viadehydrodithioacetalization. Next, the mixture was treated with a base at−20 to 60° C. to dehydrohalogenate the product to give the desired(meth)acrylated compound.

[0034] The bases used as a hydrogen-halide trap in the latter(meth)acrylation step include, but not limited to, generally-used bases;for example, trialkylamines such as trimethylamine and triethylamine,pyridine, sodium hydroxide and potassium hydroxide.

[0035] The compounds having at least one aldehyde-group includereadily-available aldehyde compounds and those having any of thefollowing structures:

[0036] wherein m represents 1 or 2; each ring may be substituted by oneor more alkyl, alkylthio or alkoxy groups having 1 or 2 carbon atoms; pand q are 0 or 1, while m-is 1 when p is 1.

[0037] The specific aldehydes which can be used, include benzaldehyde,2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-ethylbenzaldehyde,2,4-dimethylbenzaldehyde, 2,5-dimethylbenzaldehyde,3,4-dimethylbenzaldehyde, 2,4,5-trimethylbenzaldehyde,2,4,6-trimethylbenzaldehyde, 2-methoxybenzaldehyde,3-methoxybenzaldehyde, 4-methoxybenzaldehyde, 2,3-dimethoxybenzaldehyde,2,4-dimethoxybenzaldehyde, 2,5-dimethoxybenzaldehyde,3,4-dimethoxybenzaldehyde, 3,5-dimethoxybenzaldehyde,2-ethoxybenzaldehyde, 3-ethoxybenzaldehyde, 4-ethoxybanzaldehyde,phthalaldehyde, isophthalaldehyde, terephthalaldehyde,2-methylthiobenzaldehyde, 4-methylthiobenzaldehyde,4-methylthiomethylbenzaldehyde, phenylacetoaldehyde,2-thiophenealdehyde, 3-thiophenealdehyde, 3-methyl-2-thiophenealdehyde,4-methyl-2-thiophenealdehyde, 5-methyl-2-thiophenealdehyde,5-ethyl-2-thiophenealdehyde, 5-methylthiothiophene-2-aldehyde,2,3-thiophenedialdehyde, 2,5-thiophenedialdehyde, 1-naphthoaldehyde,2-naphthoaldehyde, 1,2-naphthalenedialdehyde and2,3-naphthalenedialdehyde.

[0038] Each sulfur-containing O-(meth)acrylate of this inventionrepresented by formula (1) has a main chain with the same structure andthus has an essentially equal distance between intramolecularcrosslinking points. Therefore, it is possible to select resins withdifferent optical properties by altering an aldehyde compoundconstituting a mother skeleton, without largely varying thermalproperties, mechanical properties, or the like of a resin obtained.

[0039] Similarly, when definition B is

[0040] the sulfur-containing O-(meth)acrylate compound of this inventionrepresented by formula (1) can be prepared with a sulfur-containingcarboxylic acid compound having at least two carboxyl groups in itsmolecule and the thiol compound of formula (2) by a process comprisingtwo steps of thioesterification and dehydrohalogenation.

[0041] When definition B is

[0042] the sulfur-containing O-(meth)acrylate compound of this inventionrepresented by formula (1) can be prepared with a compound having twoisocyanate groups in its molecule and the thiol compound of formula (2)by a process comprising two steps of thiourethanization anddehydrohalogenation.

[0043] When definition B is

[0044] the sulfur-containing carboxylic acid constituting a motherskeleton for the sulfur-containing O-(meth)acrylate compound is areadily available carboxylic acid, having any of the followingstructures:

[0045] HOOC—(CH₂)_(r)—S—(CH₂)_(s)—S—(CH₂)_(r)—COOH,

[0046] HOOC—(CH₂)_(r)—S—S—(CH₂)_(r)—COOH,

[0047] HOOC—(CH₂)_(r)—S—(CH₂)_(r)—COOH and

[0048] wherein r and s are an integer from 1 to 3.

[0049] The specific acids which can be used, include thiodiglycolicacid, thiodipropionic acid, 4,4-thiodibutanoic acid, dithiodiglycolicacid, dithiodipropionic acid, 4,4-dithiodibutanoic acid,methylenebis(thioglycolic acid), methylenebis(thiopropionic acid),methylenebis(thiobutanoic acid), ethylenebis(thioglycolic acid),ethylenebis(thiopropionic acid), ethylenebis(thiobutanoic acid),methinetris(thioglycolic acid), methinetris(thiopropionic acid), andmethinetris(thiobutanoic acid). These sulfur-containing O-(meth)acrylatecompounds are more hydrophilic because of having a number ofintramolecular ester bonds, which is expected to give a lens improved intintability.

[0050] When definition B is

[0051] the isocyanate compound constituting a mother skeleton for thesulfur-containing O-(meth)acrylate compound has any of the followingstructures:

[0052] OCN—(CH₂)_(r)—S—(CH₂)_(r)—NCO,

[0053] OCN—(CH₂)_(r)—S—S—(CH₂)_(r)—NCO and

[0054] OCN—(CH₂)_(r)—S—(CH₂)_(s)—S—(CH₂)_(r)—NCO

[0055] wherein r and s are an integer from 1 to 3.

[0056] The specific compounds which can be used, includediisocyanatomethyl sulfide, diisocyanatoethyl sulfide,diisocyanatopropyl sulfide, diisocyanatomethyl disulfide,diisocyanatoethyl disulfide, diisocyanatopropyl disulfide,bis(isocyanatomethylthio)methane, bis(isocyanatoethylthio)methane andbis(isocyanatopropylthio)methane. Thus obtained sulfur-containingO-(meth)acrylate compounds are expected to have improvement in arefractive index and resin strength such as impact resistance because ofhaving an intramolecular thiourethane bond.

[0057] In these reactions, if necessary, organic solvents can be used.The solvents which can be used, are, but not limited to, those which donot react with starting materials used in the reactions. Such organicsolvents include aliphatic and aromatic hydrocarbones and halogenatedhydrocarbons such as benzene, toluene, xylenes, hexane, heptane,petroleumether, chloroform, methylene chlorides and ethylene chlorides;ethers such as diethylether, dioxane and tetrahydrofuran; ketones suchas acetone and methyl ethyl ketone; and N,N-dimethylformamide. Thesolvents used are selected based on materials used, type of the reactionor the like, as appropriate.

[0058] These thiol, aldehyde, sulfur-containing carboxylic acid andisocyanate compounds may have been, if necessary, purified bydistillation or the like.

[0059] The sulfur-containing O-(meth)acrylate compounds prepared bythese processes are improved in stability as a monomer, are relativelyhard to gelate and are more easily handled in comparison withthio(meth)acrylate compounds.

[0060] The optical resin compositions of this invention include thosecomprising the sulfur-containing O-(meth)acrylate compound of thisinvention, and those comprising the sulfur-containing O-(meth)acrylatecompound of this invention and at least one of monomers co-polymerizablewith the acrylate of this invention, or polythiol compounds. For thecomposition comprising monomers other than the acrylate of thisinvention or polythiol compounds, the sulfur-containing o-(meth)acrylatecompound of this invention is contained in more than 20% by weight,preferably more than 40% by weight, more preferably more than 60% byweight, to the total amount of the sulfur-containing O-(meth)acrylatecompound and the other monomers or the polythiol compounds.

[0061] The monomers co-polymerizable with the acrylate of this inventionor the polythiol compounds may be selected, based on their purposes suchas, but not limited to, adjustment of optical properties including arefractive index, various physical properties including impactresistance and specific gravity and parameters relevant to handlingincluding viscosity of the monomer. The co-polymerizable monomers or thepolythiol compounds may be used solely or in combination of two or morecomponents.

[0062] The co-polymerizable monomers include (meth)acrylate compoundssuch as benzyl acrylate, benzyl methacrylate, butoxyethyl acrylate,butoxymethyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate,2-hydroxyethyl acrylate, 2-hydroxymethyl methacrylate, glycidylacrylate, glycidyl methacrylate, phenoxyethyl acrylate, phenoxyethylmethacrylate, phenyl methacrylate, ethylene glycol diacrylate, ethyleneglycol dimethacrylate, diethylene glycol diacrylate, diethylene glycoldimethacrylate, triethylene glycol diacrylate, triethylene glycoldimethacrylate, tetraethylene glycol diacrylate, tetraethylene glycoldimethacrylate, polyethylene glycol diacrylates, polyethylene glycoldimethacrylates, neopentyl glycol diacrylate, neopentyl glycoldimethacrylate, ethylene glycol bisglycidyl acrylate, ethylene glycolbisglycidyl methacrylate, bisphenol A diacrylate, bisphenol Adimethacrylate, 2,2-bis(4-acryloxyethoxyphenyl)propane,2,2-bis(4-methacryloxyethoxyphenyl)propane,2,2-bis(4-acryloxydiethoxyphenyl)propane,2,2-bis(4-methacryloxydiethoxyphenyl)propane, bisphenol F diacrylate,bisphenol F dimethacrylate, 1,1-bis(4-acryloxyethoxyphenyl)methane,1,1-bis(4-methacryloxyethoxyphenyl)methane,1,1-bis(4-acryloxydiethoxyphenyl)methane,1,1-bis(4-methacryloxydiethoxyphenyl)methane,1,1-bis(4-acryloxyethoxyphenyl)sulfone,1,1-bis(4-methacryloxyethoxyphenyl)sulfone,1,1-bis(4-acryloxydiethoxyphenyl)sulfone,1,1-bis(4-methacryloxydiethoxyphenyl)sulfone, dimethyloltricyclodecanediacrylate, trimethylolpropane triacrylate, trimethylolpropanetrimethacrylate, glycerol diacrylate, glycerol dimethacrylate,pentaerythritol triacrylate, pentaerythritol tetraacrylate,pentaerythritol tetramethacrylate, methylthio acrylate, methylthiomethacrylate, phenylthio acrylate, benzylthio methacrylate,xylylenedithiol diacrylates, xylylenedithiol dimethacrylates,mercaptoethyl sulfide diacrylate and mercaptoethyl sulfidedimethacrylate; allyl compounds such as allyl glycidyl ether, diallylphthalate, diallyl terephthalate, diallyl isophthalate, diallylcarbonate and diethylene glycol bis (allylcarbonate); vinyl compoundssuch as styrene, chlorostyrenes, methylstyrenes, bromostyrenes,dibromostyrene, divinylbenzenes and 3,9-divinylspiro-bi(m-dioxane); anddiisopropenylbenzene.

[0063] The polythiol compounds include 1,2-ethanedithiol,1,3-propanedithiol, 1,2,3-propanetrithiol, 2,3-dimercapto-1-propanol,diethylene glycol bis(2-mercaptoacetate), diethylene glycolbis(3-mercaptopropionate), trimethylolpropane bis(2-mercaptoacetate),trimethylolpropane bis(3-mercaptopropionate), pentaerythritoltetrakis(2-mercaptoacetate), pentaerythritoltetrakis(3-mercaptopropionate), 1,2-dimercaptobenzene,1,3-dimercaptobenzene, 1,4-dimercaptobenzene,1,2-bis(mercaptomethyl)benzene, 1,3-bis(mercaptomethyl)benzene,1,4-bis(mercaptomethyl)benzene, 1,2,3-trimercaptobenzene,1,2,4-trimercaptobenzene, 1,3,5-trimercaptobenzene,1,2,3-tris(mercaptomethyl)benzene, 1,2,4-tris(mercaptomethyl)benzene,1,3,5-tris(mercaptomethyl)benzene, 4,4′-thiobisbenzenethiol,bis(2-mercaptoethyl) sulfide, bis(2-mercaptoethylthio)methane,1,2-bis(2-mercaptoethylthio) ethane,1,3-bis(2-mercaptoethylthio)propane,1,2,3-tris(2-mercaptoethylthio)propane,tetrakis(2-mercaptoethylthiomethyl)methane,1,2-bis(2-mercaptoethylthio)-3-mercaptopropane,4,8-bis(mercaptomethyl)-3,6,9-trithia-1,11-undecanedithiol,2,5-dimercapto-1,4-dithiane, 2,5-dimercaptomethyl-1,4-dithiane and2,5-dimercaptomethyl-2,5-dimethyl-1,4-dithiane. The co-polymerizablemonomer is preferably the compound represented by the following formula(3):

[0064] wherein R represents a hydrogen atom or methyl group; t and urepresent an integer from 0 to 4; and E represents —CH₂—, —C(CH₃)₂—, —S—or —SO₂—.

[0065] The optical resin of this invention is prepared by polymerizingthe optical resin composition of this invention; specifically, bypolymerizing solely the sulfur-containing O-(meth)acrylate compound ofthis invention or co-polymerizing the sulfur-containing O-(meth)acrylatecompound of this invention and another co-polymerizable monomer or thepolythiol compound.

[0066] A polymerization procedure for providing the optical resin ofthis invention may be, but not limited to, any of the known radicalpolymerization methods.

[0067] The polymerization may be initiated by using a radical initiatorsuch as a variety of peroxides and azo compounds, or by irradiation ofUV rays, visible light, α-ray, β-ray, γ-ray, electron ray or the like orcombination thereof.

[0068] The typical radical initiators which can be used, includeperoxides such as benzoyl peroxide, dicumyl peroxide, lauroyl peroxide,di-t-butylperoxy azelate, t-butylperoxy-2-ethyl hexanoate, t-butylperoxylaurate, t-butylperoxy benzoate, t-butylperoxy-3,5,5-trimethylhexanoate,t-butylperoxy acetate, bis(4-t-butylcyclohexyl)peroxy dicarbonate andt-butylperoxy isopropyl carbonate, and azo compounds such asazobisisobutyronitrile, which may be used solely or in combination oftwo or more.

[0069] For initiation of polymerization by irradiation of UV-rays or thelike, the known photo-initiators may be also used. The typicalphoto-initiators include benzophenone, 4,4-diethylaminobenzophenone,1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone,isoamyl p-dimethylaminobenzoate, methyl 4-dimethylaminobenzoate,benzoin, benzoin ethyl ether, benzoin isobutyl ether, benzoin -isopropylether, 2,2-diethoxyacetophenone, methyl o-benzoylbenzoate,2-hydroxy-2-methyl-1-phenylpropan-1-one,2,4,6-trimethylbenzoyldiphenylphosphine oxide and bisacylphosphineoxide, which may be used solely or in combination of two or more, or incombination with any of the above radical initiators.

[0070] The typical polymerization processes for preparing the opticalresins (e.g., a plastic lens) of this invention include castingpolymerization. Specifically, the optical resin composition of thisinvention containing a radical- or photo-initiator or both, which may bereferred to as a monomer mixture, is poured between molds held by agasket, tapes or the like, during which some treatments such asdefoaming may be conducted.

[0071] Then, it is subject to irradiation of UV rays or the like, or toheating in an oven, or in combination thereof, and then a polymerizationproduct may be released.

[0072] A polymerization method or polymerization conditions forpreparing the optical resin of this invention cannot be generalizedsince they depend on the amounts and types of reagents such asinitiators as well as types and proportions of monomers.

[0073] For example, for irradiation of UV rays or the like, treatmentssuch as cooling may be applied to prevent a monomer mixture from beingoverheated, or a wavelength cut filter or the like capable of cuttingrays below a particular wavelength may be used for irradiation with onlyrays within a wavelength band necessary for the desired polymerization.For heating in an oven, temperature may be controlled to select anoptimal thermal condition. In general, the temperature may be slowlyraised from a lower one to a predetermined one which is maintained tocomplete the polymerization. The polymerization period cannot begeneralized since it depends on the amounts and types of reagents suchas initiators as well as types and proportions of monomers.

[0074] Generally, it is possible to shorten the polymerization period byUV irradiation or the like.

[0075] For molding the resin of this invention, a variety of substancessuch as chain extenders, crosslinking agents, photostabilizers, UVabsorbers, antioxidants, anti-coloring agents, dyes, perfumes andfillers, may be added, depending on a purpose, as in the known moldingmethods.

[0076] The molded resin which has been released may be, if necessary,subjected to any post-treatment such as annealing.

[0077] An optical resin obtained from the sulfur-containingO-(meth)acrylate of this invention has characteristics, that is, it hasa high refractive index and is low-dispersing, and is excellent inthermal resistance, weather resistance and, in particular, impactresistance, and that it generates less unpleasant odor duringprocessing. Furthermore, the resin of this invention can be formed as amolded resin which may be in various forms by altering a mold in thecasting polymerization, and can be, therefore, used as an optical devicesuch as lenses for eyeglasses and cameras, as well as a transparentresin for a variety of applications. In particular, it is suitable foran optical device such as lenses for eyeglasses and cameras.

[0078] Furthermore, a lens prepared with the optical resin of thisinvention may be, if necessary, subjected to physical or chemicaltreatments such as surface abrasion, antistatic treatment, hard coating,anti-reflection coating and dyeing, for improvements such as preventionof reflection; improvement in hardness, abrasion resistance or chemicalresistance; and impartation of antifogy or ornamentation.

[0079] This invention will be specifically described by the followingexamples. The properties relevant to performance of an optical resinobtained, that is, a refractive index (n_(D)), Abbe number (ν), aspecific gravity, impact resistance, odor during abrasion and appearanceare evaluated as follows.

[0080] (1) A refractive index (n_(d)) and Abbe number (ν_(d)) weremeasured at 20° C. using a Pulfrich refractometer.

[0081] (2) Appearance was visually observed.

[0082] (3) Impact resistance was evaluated by dropping an steel ballwith different weights on the center of a lens obtained from the heightof 127 cm. The result was represented by the weight of the heavieststeel ball which did not crack or break the lens.

[0083] (4) Odor during abrasion was rated according to the followingcriteria by detecting whether unpleasant sulfur odor was generatedduring cutting and abrasion of an edge of a lens with an edger. Theevaluation is as follows:

[0084] ◯; No unpleasant sulfur odor

[0085] Δ; Slight sulfur odor

[0086] ×; Unpleasant sulfur odor

EXAMPLE 1

[0087] To a reaction flask equipped with a stirring rod, a thermometerand a Dean-Stark trap with a condenser were placed 65.1 g (0.60 mol) of3-chloropropionic acid, 56.3 g (0.72 mol) of 2-mercaptoethanol, 400 mlof toluene and 3.0 g of p-toluenesulfonic acid, and the mixture was thenheated for 9 hours under a controlled pressure between 40 and 70 mmHg tomaintain reflux at 40° C. to complete dehydroesterification. The organiclayer was then washed with 5% aqueous sodium bicarbonate solution andthen water (several times).

[0088] The organic layer was dried over anhydrous magnesium sulfate andtoluene was evaporated under a reduced pressure, to give 97.7 g (0.58mol) of 2-mercaptoethyl-3-chloropropionate represented by the followingformula, as a colorless liquid.

[0089] The results of an elementary analysis for the product are shownbelow.

[0090] Composition: C₅H₉ClO₂S C H S Cl Observed (%) 35.4 5.3 19.3 21.1Calculated (%) 35.6 5.4 19.0 21.0

[0091] Its ¹H-NMR chart is shown in FIG. 1 (solvent: CDCl₃, reference:tetramethylsilane).

EXAMPLE 2

[0092] To a reaction flask equipped with a stirring rod, a thermometerand a Dean-Stark trap with a condenser were placed 21.2 g (0.20 mol) ofbenzaldehyde, 70.8 g (0.42 mol) of 2-mercaptoethyl 3-chloropropionate,0.3 g of p-toluenesulfonic acid and 300 ml of toluene, and the mixturewas then heated for 2 hours under a controlled pressure between 80 and110 mmHg to maintain reflux at 50° C. to complete dithioacetalization.After cooling, the organic layer was then washed with water (once), 5%aqueous sodium bicarbonate solution (once) and then water (severaltimes).

[0093] The organic layer was dried over anhydrous magnesium sulfate andtoluene was evaporated under a reduced pressure, to give 82.1 g (0.19mol) of a colorless liquid.

[0094] The liquid was dissolved in 200 ml of acetone, and the solutionwas placed into a reaction flask equipped with a stirring rod, athermometer and a dropping funnel. The mixture was cooled to below 10°C., and with stirring, 43.0 g (0.42 mol) of triethylamine was slowlyadded, after which the mixture was stirred for 10 hours at 25° C.

[0095] To the mixture were then added 200 ml of toluene and 200 ml ofwater to extract the reaction product into the organic layer and thenseparated the two phases. The organic layer was washed with dilutedhydrochloric acid, diluted aqueous sodium bicarbonate solution and thenwater. The organic layer was dried over anhydrous magnesium sulfate andtoluene was evaporated under a reduced pressure, to give 66.9 g of thedesired sulfur-containing O-acrylate compound represented by thefollowing formula, i.e., bis(2-acryloyloxyethyl)dithioacetal benzene(0.190 mol) as a colorless and transparent material.

[0096] The results of an elementary analysis f or the product are shownbelow.

[0097] Composition: C₁₇H₂O₄S₂ C H S Observed (%) 57.8 5.8 18.4Calculated (%) 57.9 5.7 18.2

[0098] Its ¹H-NMR chart is shown in FIG. 2 (solvent: CDCl₃, reference:tetramethylsilane).

EXAMPLE 3

[0099] Dithioacetalization and acrylation reactions were conducted asdescribed in Example 2, except that 21.2 g (0.20 mol) of benzaldehydewas replaced with 30.4 g (0.20 mol) of 4-methylthiobenzaldehyde, to give76.4 g of the sulfur-containing O-acrylate compound represented by thefollowing formula, i.e., 4-methylthiobis(2-acryloyloxyethyl)dithioacetalbenzene (0.192 mol) as a colorless and transparent material.

[0100] The results of an elementary analysis for the product are shownbelow.

[0101] Composition: C₁₈H₂₂O₄S₃ C H S Observed (%) 53.9 5.8 24.4Calculated (%) 54.2 5.6 24.1

[0102] Its ¹H-NMR chart is shown in FIG. 3 (solvent: CDCl₃, reference:tetramethylsilane).

EXAMPLE 4

[0103] Dithioacetalization and acrylation reactions were conducted asdescribed in Example 2, except that 21.2 g (0.20 mol) of benzaldehydewas replaced with 31.2 g (0.20 mol) of 1-naphthoaldehyde, to give 78.3 gof the sulfur-containing O-acrylate compound represented by thefollowing formula, i.e., 1-bis(2-acryloyloxyethyl)dithioacetalnaphthalene (0.195 mol) as a colorless and transparent material.

[0104] The results of an elementary analysis for the product are shownbelow.

[0105] Composition: C₂₁H₂₂O₄S₂ C H S Observed (%) 62.6 5.6 16.1Calculated (%) 62.7 5.5 15.9

[0106] Its ¹H-NMR chart is shown in FIG. 4 (solvent: CDCl₃, reference:tetramethylsilane).

EXAMPLE 5

[0107] Dithioacetalization and acrylation reactions were conducted asdescribed in Example 2, except that 21.2 g (0.20 mol) of benzaldehydewas replaced with 22.4 g (0.20 mol) of 2-thiophenealdehyde, to give 54.1g of the sulfur-containing O-acrylate compound represented by thefollowing formula, i.e., 2-bis(2-acryloyloxyethyl)dithioacetal thiophene(0.151 mol) as a colorless and transparent material.

[0108] The results of an elementary analysis for the product are shownbelow.

[0109] Composition: C₁₅H₁₈O₄S₃ C H S Observed (%) 50.4 5.0 26.7Calculated (%) 50.3 5.1 26.8

[0110] Its ¹H-NMR chart is shown in FIG. 5 (solvent: CDCl₃, reference:tetramethylsilane).

EXAMPLE 6

[0111] Dithioacetalization and acrylation reactions were conducted asdescribed in Example 2, except that 21.2 g (0.20 mol) of benzaldehydewas replaced with 24.0 g (0.20 mol) of phenylacetoaldehyde, to give 65.2g of the sulfur-containing O-acrylate compound represented by thefollowing formula, i.e.,phenylmethylenebis(2-acryloyloxyethyl)dithioacetal (0.178 mol) as acolorless and transparent material.

[0112] The results of an elementary analysis for the product are shownbelow.

[0113] Composition: Cl₈H₂₂O₄S₂ C H S Observed (%) 59.3 6.0 17.7Calculated (%) 59.0 6.1 17.5

[0114] Its ¹H-NMR chart is shown in FIG. 6 (solvent: CDCl₃, reference:tetramethylsilane).

EXAMPLE 7

[0115] To a reaction flask equipped with a stirring rod, a thermometerand a dropping funnel were placed 39.3 g (0.20 mol) ofmethylenebis(thioglycolic acid), 81.0 g (0.48 mol) of2-mercaptoethyl-3-chloropropionate, 0.1 g of dimethylaminopyridine and400 ml of chloroform. With stirring, to the mixture was slowly added asolution of 90.8 g (0.44 mol) of dicyclohexylcarbodiimide in 100 ml ofchloroform on a water bath, after which the mixture was stirred at 25°C. for additional 15 hours. Excessive dicyclohexylcarbodiimide wasquenched with acetic acid, and then urea formed was removed by vacuumfiltration. After evaporation of chloroform under a reduced pressure,the residual material was dissolved in 300 ml of toluene. The organiclayer was washed with 5% aqueous sodium bicarbonate solution and thenwater and dried over anhydrous magnesium sulfate. Toluene was evaporatedunder a reduced pressure to give 88.6 g (0.18 mol) of colorless liquid.

[0116] The liquid was dissolved in 300 ml of acetone and placed in areaction flask equipped with a stirring rod, a thermometer and adropping funnel. Cooling to below 10° C., to the mixture was slowlyadded 37.8 g (0.37 mol) of triethylamine, after which the mixture wasstirred at 25° C. for additional 10 hours.

[0117] Then, to the mixture were 400 ml of toluene and 300 ml of water,and the reaction product was extracted into the organic layer. Afterseparation of the two phases, the organic layer was washed with dilutedhydrochloric acid, diluted aqueous sodium bicarbonate solution andwater. The organic layer was dried over anhydrous magnesium sulfate, andtoluene was evaporated under a reduced pressure, to give 59.2 g of thedesired sulfur-containing O-acrylate compound, i.e.,methylenebis(acryloyloxyethylthio thioglycolate) (0.14 mol) as acolorless and transparent material.

[0118] The results of an elementary analysis for the product are shownbelow.

[0119] Composition: C₁₅H₂₀O₆S₄ C H S Observed (%) 42.3 5.0 29.7Calculated (%) 42.4 4.8 30.2

[0120] Its ¹H-NMR chart is shown in FIG. 7 (solvent: CDCl₃, reference:tetramethylsilane).

EXAMPLE 8

[0121] Dehydroesterification and acrylation reactions were conducted asdescribed in Example 7, except that 39.3 g (0.20 mol) ofmethylenebis(thioglycolic acid) of Example 7 was replaced with 30.0 g(0.20 mol) of thiodiglycolic acid, to give 52.7 g of thesulfur-containing O-acrylate compound represented by the followingformula, i.e., bis(acryloyloxyethylthio)-thiodiglycolate (0.14 mol) as acolorless and transparent material.

[0122] The results of an elementary analysis for the product are shownbelow.

[0123] Composition: C₁₄H₁₈O₆S₃ C H S Observed (%) 44.5 4.7 25.7Calculated (%) 44.4 4.8 25.4

[0124] Its ¹H-NMR chart is shown in FIG. 8 (solvent: CDCl₃, reference:tetramethylsilane).

EXAMPLE 9

[0125] Dehydroesterification and acrylation reactions were conducted asdescribed in Example 7, except that 39.3 g (0.20 mol) ofmethylenebis(thioglycolic acid) of Example 7 was replaced with 57.3 g(0.20 mol) of methinetris(thioglycolic acid), and the amounts of thematerials used, i.e., 2-mercaptoethyl-3-chloropropionate,dicyclohexylcarbodiimide and triethylamine were changed to 0.72 mol,0.66 mol and 0.59 mol, respectively, to give 100.6 g of thesulfur-containing O-acrylate compound represented by the followingformula, i.e., methinetris(acryloyloxyethylthio thioglycolate) (0.16mol) as a colorless and transparent material.

[0126] The results of an elementary analysis for the product are shownbelow.

[0127] Composition: C₂₂H₂₈O₉S₆ C H S Observed (%) 42.3 4.4 30.3Calculated (%) 42.0 4.5 30.6

[0128] Its ¹H-NMR chart is shown in FIG. 9 (solvent: CDCl₃, reference:tetramethylsilane).

EXAMPLE 10

[0129] To a reaction flask equipped with a stirring rod, a thermometerand a dropping funnel were placed 19.0 g (0.10 mol) ofbis(isocyanatomethylthio)methane, 15 mg of dimethyltin dichloride and100 ml of toluene. With stirring, to the mixture was slowly added 33.7 g(0.20 mol) of 2-mercaptoethyl-3-chloropropionate on a water bath, afterwhich the mixture was stirred for 2 hours at the same temperature andthen for 2 hours at 50° C. After cooling, crystals generated werefiltered, washed and dried, to give 42.5 g (0.08 mol) of white crystals.

[0130] The crystals were dissolved in 200 ml of acetone and placed in areaction flask equipped with a stirring rod, a thermometer and adropping funnel. To the solution was slowly added 17.1 g (0.17 mol) oftriethylamine, after which the mixture was stirred at 25° C. foradditional 10 hours.

[0131] Then, to the mixture were 200 ml of toluene and 200 ml of water,and the reaction product was extracted into the organic layer. Afterseparation of the two phases, the organic layer was washed with dilutedhydrochloric acid, diluted aqueous sodium bicarbonate solution andwater. The organic layer was dried over anhydrous magnesium sulfate, andtoluene was evaporated under a reduced pressure, to give 29.7 g of thedesired sulfur-containing O-acrylate compound (0.065 mol) as whitecrystals.

[0132] The results of an elementary analysis for the product are shownbelow.

[0133] Composition: C₁₅H₂₂N₂O₆S₄ C H N S Observed (%) 39.8 5.1 6.0 28.5Calculated (%) 39.6 4.9 6.2 28.2

[0134] Its ¹H-NMR chart is shown in FIG. 10 (solvent: CDCl₃, reference:tetramethylsilane).

EXAMPLES 11 TO 19

[0135] To 50 g of each product of Examples 2 to 10 was added 50 to 100mg of 2-hydroxy-2-methyl-1-phenylpropan-1-one as a photoinitiator, andthe mixture was thoroughly mixed. After fully defoaming, the mixture waspoured into a mold consisting of glass templates and a gasket. The moldwas irradiated with UV rays for 10 to 60 sec., and was then heated at120° C. for 1 hour, to polymerize the composition. After polymerization,it was slowly cooled and the molding product was removed from the mold.The physical properties of the molding products, i.e., lenses, are shownin Table 1. TABLE 1 Refractive Abbe Monomer Appearance Index NumberExample 11 Compd. of Ex. 2 CL/TR* 1.600 36.5 Example 12 Compd. of Ex. 3CL/TR 1.624 30.4 Example 13 Compd. of Ex. 4 CL/TR 1.637 27.5 Example 14Compd. of Ex. 5 CL/TR 1.609 35.8 Example 15 Compd. of EX. 6 CL/TR 1.60034.6 Example 16 Compd. of Ex. 7 CL/TR 1.602 38.5 Example 17 Compd. ofEx. 8 CL/TR 1.589 40.7 Example 18 Compd. of Ex. 9 CL/TR 1.606 38.2Example 19 Compd. of Ex. 10 CL/TR 1.632 37.5

EXAMPLE 20

[0136] To 35 g of bis(2-acryloyloxyethyl)dithioacetal benzene obtainedin Example 2 were added 15 g of bis(4-acryloxydiethoxyphenyl)methane and50 mg of 2-hydroxy-2-methyl-l-phenylpropan-1-one as a photoinitiator,and the mixture was thoroughly mixed. After fully defoaming, thecomposition was poured into a mold consisting of glass templates andtapes.

[0137] The mold was irradiated with UV rays for 10 sec., and was thenheated at 120° C. for 1 hour, to polymerize the composition. Afterpolymerization, it was slowly cooled and the molding product was removedfrom the molds. The physical properties of the molding products, i.e.,lenses, are shown in Table 2.

EXAMPLES 21 TO 26

[0138] The procedure as described in Example 20 was conducted, exceptthat the monomer compositions listed in Table 2 were used, to giveplastic lenses, whose evaluation results are shown in Table 2 togetherwith those of Example 20.

[0139] The results in Table 2 indicate that the plastic lenses ofExamples 20 to 26 were colorless and transparent; had a good balanceamong a refractive index (n_(d)), Abbe number (ν_(d)) and a specificgravity; were excellent in impact resistance; and generated nounpleasant odor during abrasion of the resins.

COMPARATIVE EXAMPLES 1 TO 3

[0140] The procedure as described in Example 20 was conducted, exceptthat the monomer compositions listed in Table 2 were used, to giveplastic lenses, whose evaluation results are shown in Table 2 togetherwith those of Examples 20 to 26.

[0141] The results in Table 2 indicate that the plastic lenses ofComparative Examples had lower impact resistance than those of Examples20 to 26, and generated sulfur odor during abrasion of the resins. TABLE2 Proportions of monomers Spec. Impact Appear- (% by weight) n_(d) ν_(d)Grav. Resist. Odor ance Example Compd. of 70 1.590 36 1.27 117 g ◯CL/TR* 20 Ex. 2 BSFA 30 Example Compd. of 65 1.591 36 1.27  67 g ◯ CL/TR21 Ex. 2 BSFA 30 Divinyl-  5 benzene Example Compd. of 65 1.598 33 1.28 67 g ◯ CL/TR 22 Ex. 3 BSFA 30 TEGDMA  5 Example Compd. of 50 1.590 321.25 117 g ◯ CL/TR 23 Ex. 4 BSFA 50 Example Compd. of 70 1.590 35 1.26 67 g ◯ CL/TR 24 Ex. 6 BSFA 30 Example Compd. of 80 1.595 38 1.36 117 g◯ CL/TR 25 Ex. 7 BSFA 20 Example Compd. of 80 1.591 38 1.37 117 g ◯CL/TR 26 Ex. 10 BSFA 15 TEGDMA  5 Comp. DTAET 80 1.609 42 1.29  16 g xCL/TR Ex. 1 DCPA 20 break Comp. AETE 70 1.581 40 1.25  16 g Δ CL/TR Ex.2 Styrene 30 break Comp. XDMET 80 1.588 39 1.31  16 g Δ CL/TR Ex. 3 BSAM20 break

What is claimed is:
 1. A sulfur-containing O-(meth)acrylate compound ofthe following formula (1):

wherein R represents hydrogen atom or methyl group; l represents aninteger from 1 to 3; B is

when B is

n is 2; m is 1 or 2; A is selected from the following groups:

wherein m represents 1 or 2; each ring may be substituted by one or morealkyl, aklylthio or alkoxy groups having 1 or 2 carbon atoms; p and qare 0 or 1, while m is 1 when p is 1; when B is

n is 1; m is 2 or 3; A is selected from the following groups:—(CH₂)_(r)—S—(CH₂)_(r)—, —(CH₂)_(r)—S—S—(CH₂)_(r)—,—(CH₂)_(r)—S—(CH₂)_(s)—S—(CH₂)_(r)— and

wherein r and s are an integer from 1 to 3; when B is

n is 1; m is 2; A is selected from the following groups:—(CH₂)_(r)—S—(CH₂)_(r)—, —(CH₂)_(r)—S—S—(CH₂)_(r)— and—(CH₂)_(r)—S—(CH₂)_(s)—S—(CH₂)_(r)— wherein r and s are an integer from1 to
 3. 2. A process for preparation of the sulfur-containingO-(meth)acrylate compound according to claim 1 , comprisingdithioacetalization, thioesterification or thiourethanization of a thiolcompound represented by the following formula (2):

wherein X represents Cl or Br; R represents hydrogen atom or methylgroup; and l represents an integer from 1 to 3; and thendehydrohalogenating the product.
 3. A process for preparation of asulfur-containing O-(meth)acrylate compound according to claim 2 ,comprising dithioacetalization with a compound having at least onealdehyde group in its molecule selected from the group consisting ofthose of the following formulae:

wherein m represents 1 or 2; each ring may be substituted by one or morealkyl or alkoxy groups having 1 or 2 carbon atoms; p and q are 0 or 1,while m is 1 when p is
 1. 4. A process for preparation of asulfur-containing O-(meth)acrylate compound according to claim 2 ,comprising thioesterification with a compound having at least twocarboxyl groups in its molecule selected from the group consisting ofthose of the following formulae:HOOC—(CH₂)_(r)—S—(CH₂)_(s)—S—(CH₂)_(r)—COOH,HOOC—(CH₂)_(r)—S—S—(CH₂)_(r)—COOH, HOOC—(CH₂)_(r)—S—(CH₂)_(r)—COOH and

wherein r and s are an integer from 1 to
 3. 5. A process for preparationof a sulfur-containing O-(meth)acrylate compound according to claim 2 ,comprising thiourethanization with a compound having two isocyanategroups in its molecule selected from the group consisting of those ofthe following formulae: OCN—(CH₂)_(r)—S—(CH₂)_(r)—NCO,OCN—(CH₂)_(r)—S—S—(CH₂)_(r)—NCO andOCN—(CH₂)_(r)—S—(CH₂)_(s)—S—(CH₂)_(r)—NCO wherein r and s are an integerfrom 1 to
 3. 6. An optical resin composition comprising thesulfur-containing O-(meth)acrylate compound according to claim 1 .
 7. Anoptical resin composition according to claim 6, comprising at least oneof monomers co-polymerizable with a sulfur-containing O-(meth)acrylatecompound and polythiol compounds.
 8. An optical resin compositionaccording to claim 7 , wherein the co-polymerizable monomer is thecompound represented by the following formula (3):

wherein R represents hydrogen atom or methyl group; t and u represent aninteger from 0 to 4; and E represents —CH₂—, —C(CH₃)₂—, —S— or —SO₂—. 9.An optical resin prepared by polymerizing a composition according to anyof claims 6 to 8 .
 10. A lens consisting of an optical resin accordingto claim 9 .
 11. A thiol compound represented by the following formula(2):

wherein X represents Cl or Br; R represents hydrogen atom or methylgroup; and l represents an integer from 1 to 3.